What is the point of all our life lessons since at the end of the day we die anyway and lose everything again?

Answer

THE phrase and THE meaning are rather big words.
Ultimately, what matters is that YOU can give meaning and meaning to your life. And the closing moment where you could say, as it were: that has now been the zini of my life, is probably so short that you barely have time to pass it on to another human being. Just think of people who, shortly before a moment of death, see their lives flash by… Some in gratitude, others in horror, and others in a sense of utter futility.
You get the meaning in life partly, but you also make it partly. That combination becomes the meaning of your life.

I wouldn’t speak of an ‘intention’. Only people have intentions. Nature, animals, life,… have no ‘intentions’ or intentions. Only man can give meaning to his/her life by giving it meaning: a direction, a goal. For example: ensuring that your children can grow up happily, ensuring that your work contributes to a better society,… or simply being able to experience a fun and healthy old age.

And if that’s not so bad, you might want to share that with others… But those others also have to get/find/make THEIR meaning in their lives. They may or may not be inspired by your way of life, depending on their life experience. You don’t have that in your hand. Even if you as a teacher or professor are allowed to pass that on to other generations in an orderly and deliberate way, it is still pure gratuitousness. With one something ‘resonates’, with the other it doesn’t. Or until they get older and say: ha, now I understand what he wanted to say.

Do you lose everything when you die?
Nobody knows. Many people have already died in the past without you being able to verify historically what their significance has ever been. However minor. But the ordinary, daily struggle with the lives of ordinary men and women has also affected their children and continues for generations…
That’s an element of the African wisdom to pay attention to the ancestors: it’s hard to figure out who exactly they were, but as current generations we try to pass on their life force to the next generations. For many Africans (but perhaps other people too) that is enough to give meaning to their lives.

This analysis can of course be supplemented with more religious interpretation. But that depends on whether or not one is convinced of what a particular religion says about life from God and after death.